BoilerFaultCodesAriston L.E.D. D Fault Code
Also written as LEDD — same fault.
The Ariston L.E.D. D fault code means: your boiler is not detecting enough water inside the system to operate safely, so it has shut down to prevent internal damage.. It appears on 6 Ariston models in our database.
Technical description: Circulation Failure: Signals that the safety pressure switch on the primary circuit has not sensed a pressure of at least 1 bar within 40 seconds of the activation of the circulation pump.
DIY fix possible
Locate the external filling loop, which is usually a silver braided hose connecting two cold water pipes under the boiler.Open the valves on both ends of the hose to allow water to enter the system.Monitor the boiler's pressure gauge until it reads between 1.0 and 1.5 bar, then securely close both valves.
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Ariston models that show the L.E.D. D fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ariston L.E.D. D fault code information on this page is sourced and cross-checked against the official Ariston service / installation manuals for each affected model.
- Ariston Eurocombi A/23 MFFI manual (PDF)
- Ariston Eurocombi 20 1mfs manual (PDF)
- Ariston Genus 27 manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026